The purpose of this research is to isolate new metabolites, especially biologically active compounds from two groups of fungi, Pyrenomycetes and Basidiomycetes. This is achieved by following the biological activity at the different stages in the isolation procedure. The structures of these compounds are then elucidated and their potential importance to organic chemistry, medicine and mycology is studied. During the course of this project several compounds previously known, were also isolated and their antibiotic activity was established for the first time.